The full, official name, pound sterling, (plural: pounds sterling) is used mainly in formal contexts and also when it is necessary to distinguish the United Kingdom currency from other currencies with the same name. Otherwise the term pound is normally used. The currency name is sometimes abbreviated to just sterling, particularly in the wholesale financial markets, but not when referring to specific amounts; for example, "Payment is accepted in sterling" but never "These cost five sterling". The abbreviations "ster." or "stg." are sometimes used. The term "British pound" is commonly used in less formal contexts, although it is not an official name of the currency. The pound sterling is also referred to as "cable" amongst forex traders. The origins of this term are attributed to the fact that in the 1800s, the dollar/pound sterling exchange rate was transmitted via transatlantic cable. Forex brokers are sometimes referred to as "cable dealers".[10]

There is apparent convergence of opinion regarding the origin of the term "pound sterling", toward its derivation from the name of a small Norman silver coin,[11] and away from its association with Easterlings (Germanic traders) or other etymologies.[12][13] Hence, the Oxford English Dictionary (and sources derived therefrom)[14][15] state that the "most plausible" etymology is derivation from the Old English steorra for "star" with the added diminutive suffix "-ling", to mean "little star" and to refer to a silver penny of the English Normans.[11] As another established source notes,[16] the compound expression was then derived:

silver coins known as "sterlings" were issued in the Saxon kingdoms, 240 of them being minted from a pound of silver... Hence, large payments came to be reckoned in "pounds of sterlings," a phrase later shortened...

—Encyclopædia Britannica, entry "pound sterling"

However, the perceived narrow window of the issuance of this coin, and the fact that coin designs changed frequently in the period in question, led Philip Grierson to reject this in favour of a more complex theory.[17] For further discussion of the etymology of "sterling", see sterling silver.

The currency sign for the pound sign is £, which is usually written with a single cross-bar (as on sterling bank notes), though a version with a double cross-bar (₤) is also sometimes seen. This symbol derives from medieval Latin documents; the Roman words libra, solidus, and denarius (£sd) referred to pounds, shillings and pence[16] in the British pre-decimal (duodecimal) currency system and the black-letter "L" was the abbreviation for libra, the basic Roman unit of weight.

A common slang term for the pound sterling or pound is quid, which is singular and plural, except in the common phrase "Quids in!" The term may have come via Italian immigrants from "scudo", the name for a number of coins used in Italy until the 19th century; or from Latin 'quid' via the common phrase quid pro quo, literally, "what for what," or, figuratively, "An equal exchange or substitution".[18]

Since decimalisation in 1971 (see Decimal Day), the pound has been divided into 100 pence (until 1981 described on the coinage as "new pence"). The symbol for the penny is "p"; hence an amount such as 50p (£0.50) properly pronounced "fifty pence" is more colloquially, quite often, pronounced "fifty pee" /fɪfti: pi:/. This also helped to distinguish between new and old pence amounts during the changeover to the decimal system. A decimal halfpenny was issued until 1984 in an attempt to stop inflation but was removed due to having a higher cost to manufacture than its face value.[19]

The Hatter's hat shows an example of the old pre-decimal system: the hat costs half a guinea (10 shillings and 6 pence)

Prior to decimalisation, the pound was divided into 20 shillings and each shilling into 12 pence, making 240 pence to the pound. The symbol for the shilling was "s."—not from the first letter of the word, but from the Latin solidus. The symbol for the penny was "d.", from the French denier, from the Latin denarius (the solidus and denarius were Roman coins). A mixed sum of shillings and pence, such as 3 shillings and 6 pence, was written as "3/6" or "3s. 6d." and spoken as "three and six" (except for "1/1," "2/1" etc., which were spoken as "one and a penny," "two and a penny," etc.). 5 shillings was written as "5s." or, more commonly, "5/–". The stroke (/) indicating shillings is also known as a solidus and was originally an adaptation of the long s which represented that word.

By the 1950s, coins of Kings George III, George IV and William IV had disappeared from circulation, but coins (at least the penny) bearing the head of any British king or queen from Queen Victoria onwards could be found in circulation. Silver coins were replaced by those in cupro-nickel in 1947 and by the 1960s the silver coins were rarely seen. Silver/cupro-nickel shillings (from any period after 1816) florins (2 shillings) remained as legal tender after decimalisation (as 5p and 10p respectively) until 1993 and are now officially demonetised.

The origins of sterling lie in the reign of King Offa of Mercia, (757–796) who introduced the silver penny. It copied the denarius of the new currency system of Charlemagne's Frankish Empire. As in the Carolingian system, 240 pennies weighed 1 pound (corresponding to Charlemagne's libra), with the shilling corresponding to Charlemagne's solidus and equal to 12d. At the time of the penny's introduction, it weighed 22.5 troy grains of fine silver (32 tower grains; about 1.5 g), indicating that the Mercian pound weighed 5,400 troy grains (the Mercian pound became the basis of the tower pound, which weighed 5,400 troy grains, equivalent to 7,680 tower grains, about 350g). At this time, the name sterling had yet to be acquired. The penny swiftly spread throughout the other Anglo-Saxon kingdoms and became the standard coin of what was to become England.

The early pennies were struck from fine silver (as pure as was available). However, in 1158, a new coinage was introduced by King Henry II (known as the Tealby penny) which was struck from 0.925 (92.5%) silver. This became the standard until the 20th century and is today known as sterling silver, named after its association with the currency. Sterling silver is harder than the 0.999 (99.9%) fine silver that was traditionally used and so sterling silver coins did not wear down as rapidly as fine silver coins. The English currency was almost exclusively silver until 1344, when the gold noble was successfully introduced into circulation. However, silver remained the legal basis for sterling until 1816. In the reign of Henry IV (1399–1413), the penny was reduced in weight to 15 grains (0.97 g) of silver, with a further reduction to 12 grains (0.78 g) in 1464.

During the reigns of Henry VIII and Edward VI, the silver coinage was drastically debased, although the pound was redefined to the troy pound of 5,760 grains (373 g) in 1526. In 1544, a silver coinage was issued containing just one third silver and two thirds copper—equating to .333 silver, or 33.3% pure. The result was a coin copper in appearance, but relatively pale in colour. In 1552, a new silver coinage was introduced, struck in sterling silver. However, the penny's weight was reduced to 8 grains (0.52 g), meaning that 1 troy pound of sterling silver produced 60 shillings of coins. This silver standard was known as the "60-shilling standard" and lasted until 1601 when a "62-shilling standard" was introduced, reducing the penny's weight to 7 23⁄31 grains (0.50 g).

Throughout this period, the size and value of the gold coinage fluctuated considerably.

In 1663, a new gold coinage was introduced based on the 22 carat fine guinea. Fixed in weight at 44½ to the troy pound from 1670, this coin's value varied considerably until 1717, when it was fixed at 21 shillings (21/-, 1.05 pounds).[20] However, despite the efforts of Sir Isaac Newton, Master of the Mint, to reduce the guinea's value, this valuation overvalued gold relative to silver when compared to the valuations in other European countries. British merchants sent silver abroad in payments whilst goods for export were paid for with gold. As a consequence, silver flowed out of the country and gold flowed in, leading to a situation where Great Britain was effectively on a gold standard. In addition, a chronic shortage of silver coins developed. This shortage was aggravated by the fact that silver was the only commodity accepted by China for exporting goods during this period. From the mid-17th century, around 28 million kilograms (62 million pounds) of silver was received by China, principally from European powers, in exchange for Chinese tea and other goods. In order to trade with China, Great Britain had to first trade with the other European nations to receive silver, which led to the East India Company redressing this trade imbalance through the indirect sale of opium to the Chinese.[21]

The pound Scots once had much the same value as the pound sterling, but it suffered far higher devaluation until in the 17th century it was pegged to sterling at a value of 12 pounds Scots = 1 pound sterling.

During the American war of independence and Napoleonic wars, Bank of England notes were legal tender and their value floated relative to gold. The Bank also issued silver tokens to alleviate the shortage of silver coins. In 1816, the gold standard was adopted officially, with the silver standard reduced to 66 shillings (66/-, £3 6s), rendering silver coins a "token" issue (i.e., not containing their value in precious metal). In 1817, the sovereign was introduced, valued at 20 shillings. Struck in 22‑carat gold, it contained 113 grains (7.3 g) of gold and replaced the guinea as the standard British gold coin without changing the gold standard. In 1825, the Irish pound, which had been pegged to sterling since 1801 at a rate of 13 Irish pounds = 12 pounds sterling, was replaced, at the same rate, with sterling.

The gold standard was suspended at the outbreak of the war in 1914, with Bank of England and Treasury notes becoming legal tender. Prior to World War I, the United Kingdom had one of the world's strongest economies, holding 40% of the world's overseas investments. However, by the end of the war the country owed £850 million (£37 billion as of 2015),[23] mostly to the United States, with interest costing the country some 40% of all government spending. In an attempt to resume stability, a variation on the gold standard was reintroduced in 1925, under which the currency was fixed to gold at its pre-war peg, although people were only able to exchange their currency for gold bullion, rather than for coins. This was abandoned on 21 September 1931, during the Great Depression, and sterling suffered an initial devaluation of some 25%.[24]

In 1940, an agreement with the U.S.A. pegged the pound to the U.S. dollar at a rate of £1 = $4.03. (Only the year before, it had been $4.86.)[26] This rate was maintained through the Second World War and became part of the Bretton Woods system which governed post-war exchange rates. Under continuing economic pressure, and despite months of denials that it would do so, on 19 September 1949 the government devalued the pound by 30.5% to $2.80. The move prompted several other currencies to be devalued against the dollar.

In 1961, 1964 and 1966, the pound came under renewed pressure since the exchange rate against the dollar was considered too high. In the summer of 1966, with the value of the pound falling in the currency markets, exchange controls were tightened by the Wilson government. Among the measures, tourists were banned from taking more than £50 out of the country, until the restriction was lifted in 1979. The pound was eventually devalued by 14.3% to $2.40 on 18 November 1967.

Until decimalisation, amounts were stated in pounds, shillings, and pence, with various widely understood notations. The same amount was denoted by 32s 6d, 32/6, £1 12s 6d, £1/12/6. It was customary to specify some prices (for example professional fees and auction prices for works of art) in guineas (one guinea was 21 shillings) although there were no guinea coins or notes.

On 15 February 1971, the UK decimalised, replacing the shilling and penny with a single subdivision, the new penny. £1 12s 6d became £1.62½. The word "new" was omitted from coins after 1981.

With the breakdown of the Bretton Woods system, the pound floated from August 1971 onwards. It at first appreciated a little, rising to almost $2.65 in March 1972, from $2.42 when it had been fixed. The sterling area effectively ended at this time when the majority of its members also chose to float freely against the pound and the dollar.

James Callaghan came to office in 1976. He was immediately told the economy was facing huge problems, according to documents released in 2006 by the National Archives.[27] The effects of the 1973 oil crisis were still being felt, with inflation rising to over 27% in 1975.[28] Financial markets were beginning to believe the pound was overvalued, and in April that year The Wall Street Journal advised the sale of sterling investments in a story titled "Goodbye, Great Britain. It was nice knowing you".[29] At the time the UK government was running a budget deficit, and Labour's strategy emphasised high public spending. Callaghan was told there were three possible outcomes: a disastrous free fall in sterling, an internationally unacceptable siege economy, or a deal with key allies to prop up the pound while painful economic reforms were put in place. The US government feared the crisis could endanger NATO and the European Economic Community (EEC), and in light of this the US Treasury set out to force domestic policy changes. In November 1976 the International Monetary Fund (IMF) announced the conditions for a loan, including deep cuts in public expenditure.[30]

The Conservative Party was elected to office in 1979, on a programme of fiscal austerity. Initially the pound rocketed, moving above US$2.40, as interest rates rose in response to the monetarist policy of targeting money supply. The high exchange rate was widely blamed for the deep recession of 1981. Sterling fell sharply after 1980; at its lowest, the pound stood at just $1.03 in March 1985, before rising to $1.70 in December 1989.[31]

In 1988, Margaret Thatcher's Chancellor of the Exchequer, Nigel Lawson, decided that the pound should "shadow" the West German Deutsche Mark, with the unintended result of a rapid rise in inflation as the economy boomed due to inappropriately low interest rates. (For ideological reasons, the Conservative Government declined to use alternative mechanisms to control the explosion of credit. For this reason, former Prime Minister Edward Heath referred to Lawson as a "one club golfer").[32]

Following German re-unification in 1990, the reverse held true, as high borrowing costs to fund Eastern reconstruction, a need exacerbated by the political choice to make the Ostmark equivalent to the Deutsche Mark (DM), meant rates in other countries shadowing the DM, especially the UK, were far too high relative to domestic circumstances, leading to a housing decline and recession.

'Black Wednesday' saw interest rates jump from 10% to 15% in an unsuccessful attempt to stop the pound from falling below the ERM limits. The exchange rate fell to DM2.20. Those who had argued[33] for a lower GBP/DM exchange rate were vindicated as the cheaper pound encouraged exports and contributed to the economic prosperity of the 1990s.

In 1997, the newly elected Labour government handed over day-to-day control of interest rates to the Bank of England (a policy that had originally been advocated by the Liberal Democrats).[34] The Bank is now responsible for setting its base rate of interest so as to keep inflation in the Consumer Price Index (CPI) very close to 2%. Should CPI inflation be more than one percentage point above or below the target, the governor of the Bank of England is required to write an open letter to the Chancellor of the Exchequer explaining the reasons for this and the measures which will be taken to bring this measure of inflation back in line with the 2% target. On 17 April 2007, CPI inflation was reported at 3.1% (inflation of the Retail Prices Index was 4.8%). Accordingly, and for the first time, the Governor had to write publicly to the government explaining why inflation was more than one percentage point higher than its target.[35]

As a member of the European Union, the United Kingdom could adopt the euro as its currency. However, the subject remains politically controversial. Gordon Brown, then Chancellor of the Exchequer, ruled out membership for the foreseeable future, saying that the decision not to join had been right for Britain and for Europe.[36]

The government of former Prime Minister Tony Blair had pledged to hold a public referendum to decide on membership should "five economic tests" be met, to ensure that adoption of the euro would be in the national interest. In addition to these internal (national) criteria, the UK would have to meet the European Union's economic convergence criteria (Maastricht criteria), before being allowed to adopt the euro. The Conservative and Liberal Democrat coalition government ruled out joining the euro for the parliamentary term. Currently, the UK's annual government deficit, as a percentage of the GDP, is above the defined threshold.

The idea of replacing the pound with the euro has been controversial with the British public, partly because of the pound's identity as a symbol of British sovereignty and because it would, according to critics, lead to suboptimal interest rates, harming the British economy.[37] In December 2008, the results of a BBC poll of 1000 people suggested that 71% would vote no to the euro, 23% would vote yes to joining the European single currency, while 6% said they were unsure.[38] The pound did not join the Second European Exchange Rate Mechanism (ERM II) after the euro was created. Denmark and the UK have opt-outs from entry to the euro. Technically, every other EU nation must eventually sign up.

The pound and the euro fluctuate in value against one another, although there may be correlation between movements in their respective exchange rates with other currencies such as the US dollar. Inflation concerns in the UK led the Bank of England to raise interest rates in late 2006 and 2007. This caused the pound to appreciate against other major currencies and, with the US dollar depreciating at the same time, the pound hit a 15-year high against the US dollar on 18 April 2007, reaching US$2 the day before, for the first time since 1992. The pound and many other currencies continued to appreciate against the dollar; sterling hit a 26-year high of US$2.1161 on 7 November 2007 as the dollar fell worldwide.[44] From mid-2003 to mid-2007, the pound/euro rate remained range-bound (within ± 5%) of €1.45.[45]

Following the global financial crisis in late 2008, however, the pound has since depreciated at one of the fastest rates in history, reaching $1.38 per £1 on 23 January 2009[46] and falling below €1.25 against the euro in April 2008.[47] A further decline occurred during the remainder of 2008, most dramatically on 29 December when its euro rate hit an all-time low at €1.0219, while its US dollar rate depreciated.[48][49] The pound appreciated in early 2009 reaching a peak against the euro in mid-July of €1.17. The following months the pound remained broadly steady against the euro, with the pound's current (27 May 2011) value at €1.15 and US$1.65.

The process saw the Bank of England creating new money for itself, which it then used to purchase assets such as government bonds, secured commercial paper, or corporate bonds.[51] The initial amount stated to be created through this method was £75 billion, although Chancellor of the ExchequerAlistair Darling had given permission for up to £150 billion to be created if necessary.[52] It was expected that the process would occur over a period of three months with results only likely in the long term.[50] By 5 November 2009, some £175 billion had been injected using quantitative easing and the effectiveness of the process remained less successful in the long term. In July 2012, the final increase in the asset purchases finance meant QE had peaked at £375 billion, then holding solely UK Government bonds, representing one third of the UK national debt.[53]

The Bank of England had stated (2009) that the decision had been taken to prevent the rate of inflation falling below the 2% target rate.[51] Mervyn King, the Governor of the Bank of England, also had suggested there were no other monetary options left as interest rates had already been cut to their lowest level ever (0.5%) and it was unlikely that they would be cut further.[52]

The inflation rate per annum rose in following years, reaching 5.2% (based on Consumer Price Index) in September 2011, then decreased to around 2.5% in the following year.[54]

The silver penny (plural: pence; abbreviation: d) was the principal and often sole coin in circulation from the 8th century until the 13th century. Although some fractions of the penny were struck (see farthing and halfpenny), it was more common to find pennies cut into halves and quarters to provide smaller change. Very few gold coins were struck, with the gold penny (worth 20 silver pence) a rare example. However, in 1279, the groat, worth 4d, was introduced, with the half groat following in 1344. 1344 also saw the establishment of a gold coinage with the introduction (after the failed gold florin) of the noble worth six shillings and eight pence ('6/8') (i.e. 3 to the pound), together with the half and quarter noble. Reforms in 1464 saw a reduction in value of the coinage in both silver and gold, with the noble renamed the ryal and worth 10/- (i.e. 2 to the pound) and the angel introduced at the noble's old value of 6/8.

The reign of Henry VII saw the introduction of two important coins, the shilling (abbr.: s; known as the testoon) in 1487 and the pound (known as the sovereign, abbr.: £ or L) in 1489. In 1526, several new denominations of gold coins were added, including the crown and half crown worth five shillings (5/-), and two shillings and six pence (2/6, two and six) respectively. Henry VIII's reign (1509–1547) saw a high level of debasement which continued into the reign of Edward VI (1547–1553). This debasement was halted in 1552, and a new silver coinage was introduced, including coins for 1d, 2d, 3d, 4d and 6d, 1/-, 2/6 and 5/-. In the reign of Elizabeth I (1558–1603), silver ¾d and 1½d coins were added, but these denominations did not last. Gold coins included the half-crown, crown, angel, half-sovereign and sovereign. Elizabeth's reign also saw the introduction of the horse-drawn screw press to produce the first "milled" coins.

Following the succession of the Scottish King James VI to the English throne, a new gold coinage was introduced, including the spur ryal (15/-), the unite (20/-) and the rose ryal (30/-). The laurel, worth 20/-, followed in 1619. The first base metal coins were also introduced, tin and copperfarthings. Copper halfpenny coins followed in the reign of Charles I. During the English Civil War, a number of siege coinages were produced, often in unusual denominations.

Following the restoration of the monarchy in 1660, the coinage was reformed, with the ending of production of hammered coins in 1662. The guinea was introduced in 1663, soon followed by the ½, 2 and 5 guinea coins. The silver coinage consisted of denominations of 1d, 2d, 3d, 4d and 6d, 1/-, 2/6 and 5/-. Due to the widespread export of silver in the 18th century, the production of silver coins gradually came to a halt, with the half crown and crown not issued after the 1750s, the 6d pence and 1/- stopping production in the 1780s. One response was the introduction of the copper 1d and 2d coins and the gold ⅓ guinea (7/-) in 1797. The copper penny was the only one of these coins to survive long.

To alleviate the shortage of silver coins, between 1797 and 1804, the Bank of England counterstamped Spanish dollars (8 reales) and other Spanish and Spanish colonial coins for circulation. A small counterstamp of the King's head was used. Until 1800, these circulated at a rate of 4/9 for 8 reales. After 1800, a rate of 5/- for 8 reales was used. The Bank then issued silver tokens for 5/- (struck over Spanish dollars) in 1804, followed by tokens for 1/6 and 3/- between 1811 and 1816.

In 1816, a new silver coinage was introduced in denominations of 6d, 1/-, 2/6 (half-crown) and 5/- (crown). The crown was only issued intermittently until 1900. It was followed by a new gold coinage in 1817 consisting of 10/- and £1 coins, known as the half sovereign and sovereign. The silver 4d coin was reintroduced in 1836, followed by the 3d in 1838, with the 4d coin issued only for colonial use after 1855. In 1848, the 2/- florin was introduced, followed by the short-lived double florin in 1887. In 1860, copper was replaced by bronze in the farthing (quarter penny, ¼d), halfpenny and penny.

During the First World War, production of the half sovereign and sovereign was suspended and, although the gold standard was restored, the coins saw little circulation thereafter. In 1920, the silver standard, maintained at .925 since 1552, was reduced to .500. In 1937, a nickel-brass 3d coin was introduced; the last silver 3d coins were issued seven years later. In 1947, the remaining silver coins were replaced with cupro-nickel. Inflation caused the farthing to cease production in 1956 and be demonetised in 1960. In the run-up to decimalisation, the halfpenny and half-crown were demonetised in 1969.

2007: By now the value of copper in the pre-1992 1p/2p coins (which are 97% copper) exceeded those coins' face value to such an extent that melting down the coins by entrepreneurs was becoming worthwhile (with a premium of up to 11%, with smelting costs reducing this to around 4%)—although this is illegal, and the market value of copper has subsequently fallen dramatically from these earlier peaks.

2014: It was announced that in 2017 the pound coin will change to a more secure twelve sided coin to discourage forgery.

At present, the oldest circulating coins in the U.K. are the 1p and 2p copper coins introduced in 1971. Before decimalisation, a handful of change might have contained coins 100 or more years old, bearing any of five monarchs' heads.

In April 2008 an extensive redesign of the coinage was unveiled. The new designs were issued gradually into circulation, starting in summer 2008. The new reverses of the 1p, 2p, 5p, 10p, 20p and 50p coins feature parts of the Royal Shield, and the new pound coin depicts the whole shield. The coins have the same sizes, shapes and weights as those with the old designs, which will continue to circulate.

The first sterling notes were issued by the Bank of England shortly after its foundation in 1694. Denominations were initially written on the notes at the time of issue. From 1745, the notes were printed in denominations between £20 and £1000, with any odd shillings added in hand. £10 notes were added in 1759, followed by £5 in 1793 and £1 and £2 in 1797. The lowest two denominations were withdrawn following the end of the Napoleonic wars. In 1855, the notes were converted to being entirely printed, with denominations of £5, £10, £20, £50, £100, £200, £300, £500 and £1000 issued.

The Bank of Scotland began issuing notes in 1695. Although the pound scots was still the currency of Scotland, these notes were denominated in sterling in values up to £100. From 1727, the Royal Bank of Scotland also issued notes. Both banks issued some notes denominated in guineas as well as pounds. In the 19th century, regulations limited the smallest note issued by Scottish banks to be the £1 denomination, a note not permitted in England.

With the extension of sterling to Ireland in 1825, the Bank of Ireland began issuing sterling notes, later followed by other Irish banks. These notes included the unusual denominations of 30/- and £3. The highest denomination issued by the Irish banks was £100.

In 1826, banks at least 65 miles (105 km) from London were given permission to issue their own paper money. From 1844, new banks were excluded from issuing notes in England and Wales but not in Scotland and Ireland. Consequently, the number of private banknotes dwindled in England and Wales but proliferated in Scotland and Ireland. The last English private banknotes were issued in 1921.

In 1914, the Treasury introduced notes for 10/- and £1 to replace gold coins. These circulated until 1928, when they were replaced by Bank of England notes. Irish independence reduced the number of Irish banks issuing sterling notes to five operating in Northern Ireland. The Second World War had a drastic effect on the note production of the Bank of England. Fearful of mass forgery by the Nazis (see Operation Bernhard), all notes for £10 and above ceased production, leaving the bank to issue only 10/-, £1 and £5 notes. Scottish and Northern Irish issues were unaffected, with issues in denominations of £1, £5, £10, £20, £50 and £100.

The Bank of England reintroduced £10 notes in 1964. In 1969, the 10/- note was replaced by the 50p coin as part of the preparation for decimalisation. £20 Bank of England notes were reintroduced in 1970, followed by £50 in 1981.[55] Following the introduction of the £1 coin in 1983, Bank of England £1 notes were withdrawn in 1988. Scottish and Northern Irish banks followed, with only the Royal Bank of Scotland continuing to issue this denomination.

UK notes include raised print (e.g. on the words "Bank of England"); watermarks; embedded metallic thread; holograms; and fluorescent ink visible only under UV lamps. Three printing techniques are involved: offset litho, intaglio and letterpress; and incorporate a total of 85 specialized inks.[56]

The £5 polymer banknote, issued by Northern Bank in 2000, is the only polymer note currently in circulation, although Northern Bank also produces paper-based £10, £20 and £50 notes.

The Bank of England produces notes named "giant" and "titan".[57] A giant is a one million pound note, and a titan is a one hundred million pound bank note,[58] of which there are about 40. Giants and titans are used only within the banking system.

As the central bank of the United Kingdom which has been delegated authority by the government, the Bank of England sets the monetary policy for the British pound by controlling the amount of money in circulation. It has a monopoly on issuance of banknotes in England and Wales, and regulates the amount of banknotes issued by seven authorized banks in Scotland and Northern Ireland.[59]HM Treasury has reserve powers to give orders to the committee "if they are required in the public interest and by extreme economic circumstances" but such orders must be endorsed by Parliament within 28 days.[60]

Unlike banknotes which have separate issuers in Scotland and Northern Ireland, all UK coins are issued by the Royal Mint, which is an independent enterprise (wholly owned by the Treasury) which also mints coins for other countries.

In Britain's Crown Dependencies, the Manx pound, Jersey pound, and Guernsey pound are unregulated by the Bank of England and are issued independently.[61] However, they are maintained at a fixed exchange rate by their respective governments, and Bank of England notes have been made legal tender on the islands, forming a sort of one-way de facto currency union. These currencies do not have ISO 4217 codes so "GBP" is usually used to represent all of them; informal codes are used where the difference is important.

Legal tender in the UK is defined such that "a debtor cannot successfully be sued for non-payment if he pays into court in legal tender." Parties can alternatively settle a debt by other means with mutual consent. Strictly speaking it is necessary for the debtor to offer the exact amount due as there is no obligation for the other party to provide change.[63]

Throughout the UK, £1 and £2 coins are legal tender for any amount, with the other coins being legal tender only for limited amounts. Bank of England notes are legal tender for any amount in England and Wales, but not in Scotland or Northern Ireland.[64] (Bank of England 10/- and £1 notes were legal tender, as were Scottish banknotes, during World War II under the Currency (Defence) Act 1939, repealed on 1 January 1946.) Channel Islands and Isle of Man banknotes are legal tender only in their respective jurisdictions.

Scottish, Northern Irish, Channel Islands, Isle of Man, Gibraltar, and Falkland banknotes may be offered anywhere in the United Kingdom, although there is no obligation to accept them as a means of payment, and acceptance varies. For example, merchants in England generally accept Scottish and Northern Irish bills, but some unfamiliar with them may reject them.[65] Merchants in England generally do not accept Jersey, Guernsey, Isle of Man, Gibraltar, and Falkland notes, but Isle of Man notes are generally accepted in Scotland and Northern Ireland. Bank of England notes are generally accepted in the Falklands and Gibraltar, but for example Scottish and Northern Irish notes are not.[66] Since all of the bills are denominated in pounds sterling, banks will exchange them for locally issued bills at face value, though some in the UK have had trouble exchanging Falkland Islands pounds.[67]

Commemorative £5 and 25p (crown) coins, rarely seen in circulation, are legal tender, as are the bullion coins issued by the Mint.

In 2006, the House of Commons Library published a research paper which included an index of prices in pounds for each year between 1750 and 2005, where 1974 was indexed at 100.[70]

Regarding the period 1750–1914 the document states: "Although there was considerable year on year fluctuation in price levels prior to 1914 (reflecting the quality of the harvest, wars, etc.) there was not the long-term steady increase in prices associated with the period since 1945". It goes on to say that "Since 1945 prices have risen in every year with an aggregate rise of over 27 times".

The value of the index in 1751 was 5.1, increasing to a peak of 16.3 in 1813 before declining very soon after the end of the Napoleonic Wars to around 10.0 and remaining in the range 8.5–10.0 at the end of the nineteenth century. The index was 9.8 in 1914 and peaked at 25.3 in 1920, before declining to 15.8 in 1933 and 1934—prices were only about three times as high as they had been 180 years earlier.[71]

Inflation had a dramatic effect during and after World War II—the index was 20.2 in 1940, 33.0 in 1950, 49.1 in 1960, 73.1 in 1970, 263.7 in 1980, 497.5 in 1990, 671.8 in 2000 and 757.3 in 2005.

The following table shows the equivalent amount of goods that, in a particular year, could be purchased with £1.[72][73]

The table shows that from 1971 through 2012 the British pound has lost about 92% of its buying power.

^Wren-Lewis, Simon, et al, 1991. "Evaluating the U.K.'s Choice of Entry Rate into the ERM," The Manchester School of Economic & Social Studies, University of Manchester, vol. 59(0), pages 1-22, Supplemen.

A Retrospective on the Bretton Woods System : Lessons for International Monetary Reform (National Bureau of Economic Research Project Report) By Barry Eichengreen (Editor), Michael D. Bordo (Editor) Published by University of Chicago Press (1993) ISBN 0-226-06587-1

The political pound: British investment overseas and exchange controls past—and future? By John Brennan Published By Henderson Administration (1983) ISBN 0-9508735-0-0